Handle duplicate kinds in listener allowed kinds

Author: fabian4

internal/controller/state/graph/gateway_listener.go

@@ -287,7 +287,8 @@ func getAndValidateListenerSupportedKinds(listener v1.Listener) (
 	}
 
 	if listener.AllowedRoutes != nil && listener.AllowedRoutes.Kinds != nil {
-		supportedKinds = make([]v1.RouteGroupKind, 0, len(listener.AllowedRoutes.Kinds))
+		unique := make(map[string]struct{})
+		supportedKinds = make([]v1.RouteGroupKind, 0)
 		for _, kind := range listener.AllowedRoutes.Kinds {
 			if !validProtocolRouteKind(kind) {
 				group := v1.GroupName
@@ -298,7 +299,12 @@ func getAndValidateListenerSupportedKinds(listener v1.Listener) (
 				conds = append(conds, conditions.NewListenerInvalidRouteKinds(msg)...)
 				continue
 			}
-			supportedKinds = append(supportedKinds, kind)
+			// Use kind as key for uniqueness
+			key := string(kind.Kind)
+			if _, exists := unique[key]; !exists {
+				unique[key] = struct{}{}
+				supportedKinds = append(supportedKinds, kind)
+			}
 		}
 		return conds, supportedKinds
 	}

internal/controller/state/graph/gateway_listener_test.go

@@ -382,6 +382,20 @@ func TestGetAndValidateListenerSupportedKinds(t *testing.T) {
 			name:      "valid and invalid kinds",
 			expected:  []v1.RouteGroupKind{HTTPRouteGroupKind},
 		},
+		{
+			protocol: v1.HTTPProtocolType,
+			kind: []v1.RouteGroupKind{
+				HTTPRouteGroupKind,
+				GRPCRouteGroupKind,
+				GRPCRouteGroupKind,
+			},
+			expectErr: false,
+			name:      "handle duplicate kinds",
+			expected: []v1.RouteGroupKind{
+				HTTPRouteGroupKind,
+				GRPCRouteGroupKind,
+			},
+		},
 		{
 			protocol: v1.TLSProtocolType,
 			kind: []v1.RouteGroupKind{